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lim(x开三次方-1)/(x开二次方-1)x趋近于1

题目详情
lim(x开三次方-1)/(x开二次方-1) x趋近于1
▼优质解答
答案和解析
显然
x^1/3 -1=(x-1) /(x^2/3 +x^1/3 +1)
x^1/2 -1=(x-1) /(x^1/2+1)
所以
lim(x趋于1) (x^1/3 -1) / (x^1/2 -1)
=lim(x趋于1) [(x-1) /(x^2/3 +x^1/3 +1)] / [(x-1) /(x^1/2+1)]
=lim(x趋于1) (x^1/2+1) / (x^2/3 +x^1/3 +1)
= 2/3